Pneumatic-tool retainer.



No. 885,537. PATENTED APR. 21. 1908. B. J. SHOFPNER.

PNEUMATIC TOOL RETAINER.

APPLICATION FILED DEO.2'I. 1907.

EDWARD J. SHOFFNER, OF ROANOKE, VIRGINIA, ASSIGNOR'OF FIFTY-ONE ONE-HUN-DREDTHS TO G-URDON W. MERRELL, OF ROANOKE, VIRGINIA.

PNEUMATIC-TOOL RETAINER.

Specification of Letters Patent.

Patented April 21, 1908.

. provision was made, been danger of the accidental shooting out of theplunger or of the rivet set or button set employed, with consequentliability of the loss of these parts and of injury to persons or objectswho may be struck thereby, since the piston in tools of this characteris usually reciprocatcd under a high pressure of motive fluid ofapproximately one hundred pounds or over to the square inch.

The object of the present invention is to provide a novel constructionand assemblage of devices for preventing the accidental shooting out ofthe plunger and of the rivet set, button set or other tool, that may beoperated upon by the plunger and to the above ends I employ in carryingout my invention, a retainer or retaining sleeve of the same or lesserouter diameter than the outer diameter of the cylinder, said sleevebeing preferably in threaded engagement with a reduced end of theriveter cylinder and having an outer inwardly turned flange throughwhich the end or head of the button set or other working tool projects,whereby a cham her is formed within said retainer for the button setshoulder and within said chamber is contained a spring which is oflesser length or area than the longitudinal distance between theshoulder of the button set and the inner Wall of the inwardly turnedflange of the retainer, said button set being provided with a rearwardlyextending shank of lesser diameter than said shoulder or head proper,which latter is encircled by said spring, said shank extending into thebore of the riveting cylinder, and being adapted to be harnmered upon bythe reciprocating piston, the foregoing parts being so constructed andcollocated that the impact of the hammering piston is imparted directlyto the shank of the button set and thence directly upon the rivet orother point without the force of the blow being impaired or diminishedin any particular.

F or the purpose of explaining my invention, the accompanying drawingillustrates a satisfactory reduction of the same to practice, but theimportant instrumentalities thereof may be varied, and so it is to beunderstood that the invention is not limited to the speci'licarrangement and organization shown and described.

Figure 1. represents a longitudinal sectional view of a tool retainerand its adjuncts, embodying my invention, the cylinder and rear of thehammer being shown in elevation. Fig. 2 represents a side elevation ofthe tool retainer in detached position. Fig. 3 represents a sideelevation of the spring employed. Fig. l represents a vertical sectionalview, partly in elevation, showing the position the parts assume indriving a rivet.

Similar numerals of reference indicate corresponding parts in thefigures.

Referring to the drawings :1 designates a pneumatic tool retainer, thesame consisting of a sleeve having the opening 2 through its forwardend, which is of lesser diameter than the inner bore 3 of the retainer,the forward portion of said bore terminating in the wall 4, whereby achamber 5 is formed between said bore 3 and the head or body of thebutton set 6, around which is the spring 7 which is preferably of theflattened con struction seen in Figs. 1 and 2, although it is apparentthat a round or other coil spring or its equivalent may be employedwithout departing from the spirit of my invention.

8 designates a shoulder on the button set, the latter being locatedbetween the spring 7 and the reduced extremity 9 of the rivetingcylinder 10, the rear portion of said sleeve or retainer 1. beingthreaded as indicated at 11, so as to engage the reduced threaded end 9of said cylinder.

12 designates the shank of the button set or other working tool, thesame being of less diameter than the head 6 or the shoulder 8 thereof,and being received in the chamber 13 which as will be understood fromFig. 1, is of slightly larger diameter than the bore 14 of the rivetingcylinder 10, in which the piston 15 ircciprocates, the latter beingpreferably the shape of albeit of uniform diameter throughoutitsglengthlandjprovidedjvith suitable valve mechanism (not shown) forthe admission and exhaust of the motive fluid to the opposite ends ofthe cylinder.

16 designates the grasping handle of the tool, which is in threaded orother engage ment with the cylinder 10, said handle being provided withthe thumb or finger piece 17, whereby the admission of the motive fluidthrough the inlet or pressure supply duct 18 to the valve mechanism (notshown) is controlled according to requirements, as will be familiar tothose skilled in the art.

I desire to call especial attention to the fact that the chamber 5within the retainer 1 is of greater longitudinal area than the length ofthe spring 7 whereby there is a chamber formed of such area that theimpact or blows of the hammering piston 15 are always transmitteddirectly from the shank 12 of the button set 6 to the head thereof andthence directly upon the rivet or other article 19 to be headed ortreated without any impairment or diminishing of the elliciency or forceof the blow by reason of the interposition oi the spring 7. In otherwords, it will be apparent to those skilled in the art that when thebutton set or other working tool 6 is applied to the rivet or otherdesired point, as indicated in Fig. 4, the wall or shoulder 4 has noeffect upon the spring 7 or the button set shoulder 8 other than to keepsaid spring from slipping out of the retainer, so that said shoulder lis usually in contact with the ad jacent extremity of the spring onlywhen the button set or other working tool is in position, seen in Fig.4:, with respect to the rivet or other material operated upon, and whilethe tool is in operation.

It will be understood that when the button set or other working tool 6is applied to the rivet or other desired point and the pistion strikesthe set, as for example, as shown in Fig. 4, the shank 12 will bepartially within the chamber 13 and the shoulder 8 will be out ofcontact with the reduced end 9 and the spring 7, as will be readilyunderstood by those skilled in the art, it being apparent that by myconstruction of chamber 5 hav ing the requisite proportions relative tothe button set 6, spring 7 and shoulder 8, I am enabled to obtain thegreatest elliciency from the hammering piston and to preserve the lifeof the sleeve or retainer 1 and to also minimize vibration, since theshoulder will be out of contact with any parts which tend to impair theefliciency of the blow of the hammering piston.

It will be understood by those skilled in this art that in the practicaloperation of my device, the workman grasps the tool handle 16, seen atthe right of Fig. 1, in his right hand and with his left hand grasps thetool cylinder 10 at or near the sleeve 1, whereby the button set orworking tool is readily applied to the red-hot rivet 19 or other desiredpoint and the piston 15 having been caused to reciprocate, its impactupon the button set, as indicated in Fig. i, ell'ects the heading of therivet. Inasmuch as the pistons in tools of this character reciprocatefrom six to eight hundred times per minute, or so rapidly that the blowsappear to be continuous, and since it is furthe essential in standard.pneumatic hammering or riveting tools, that an ordinary sized rivet ofsay seven-eighths of an inch to an inch and an eighth in diameter shallbe headed in from ten to fifteen seconds in practice, it will be seenthat it is of the highest importance that the blows from the impact ofthe hammering piston be imparted not only to the button set, but fromthe latter to the heated rivet as instantaneously and directly aspossible, or in other words, it is essential that there be noobstruction, spring or other cushioning device between the shoulder S ofthe button set and the inner wall i of the inclosing sleeve of suchlength or dimensions as to wholly as the space between said shoulder andwall and thus impair or diminish the eiiiciency of the blows of thehammer, and there must, under ordinary conditions, during the hammeringupon the button set or the driving or the rivet, be no undue orintentional contact of the ends of the cushioning device between saidbutton set shoulder S and said inner wall l of said retainer, which willimpair the efficiency or diminish the force of the blows of thehammering piston. i it will be apparent to those ski led in the art thatif there is a constant contact between the button set shoulder S and theinner wall or flange l of the retaining sleeve 1, or if the entire spacebetween said wall and shoulder fully occupied by a spring or othercushioning device so as not to permit an entirely free movement of saidshoulder 8 and button set, not only will the e'fliciency of the blows oithe piston upon the button set be din'iinished to a serious extent, butin addition a retaining sleeve of this character will in a short time 1ecome in practice fractured and worthless and the vibration will beincreased to an undesirable extent. it is therefore essential that aninternal chamber, as 5, be provided within the retaining de ice 1 and itis also essential that the area and dimensions e'l such chamber be ofproper proportion with respect to the button set shoulder 8 and thespring 7, so that the button set and button set shoulder may havesufiicient free play for the reasons above explained.

Furthermore, it is essential in the practical application of thesehammering tools, especially when used for riveting in corners, or fordriving rivets upon lofty structures, such as bridges, and otherstructural steel buildings where many rivets must be driven in cornersof angle irons, T-beams, I-beams and the like, that the button set endof the cylinder be kept as free as possible from any extraneoustransverse attachments, such as clamps, springs, rods or the like, whichinterfere not only with the handling of the tool, but (What is moreserious) interfere with and prohibit the application of the set to thedriving of rivets in corners or other similar in accessible places,which under any conditions are more or less difficult of access.

In my present invention it will be apparent to those skilled in the artthat by making the retainer 1 of the same external diameter as thehammer cylinder 10 or of slightly lesser diameter, as I have sometimesfound it desirable in practice to do, the forward end of the tool can bereadily applied to and directed upon the work at any desired point,under all conditions and there is furthermore no obstruction orinterference to the left hand of the workman in handling or manipulatingthe forward end of the tool, since the joint between the retainer 1 andthe cylinder 10 presents the appearance of a practically unbrokencontinuity, whereby the appearance. of the hammer is not detracted from.It will furthermore be apparent that the retainer 1 serves as a neat andell'ective closure for the end of the cylinder, thereby preventing theentrance of dirt, chips or other extraneous matter, to the bore 14 ofthe cylinder, which is a frequent cause of sticking and scoring of thepiston.

As is well known to those skilled in the art, hammers of this characterare subjected to very severe usage and often times when a piston shootsout accidentally, as into sand or dirt, it is sometimes replaced intothe cylinder without being thoroughly cleaned or wi ed off, which is asource of constant troub e, whereby my device avoids all such trouble.

It will be apparent that while I have shown my'device as applicable to abutton set or rivet set, it is equally applicable to any otherconstruction of working tool.

So far as I am aware I am the first in the art to produce thecombination with a cylinder end, of a sleeve secured thereto and havingachamber within it of greater longitudinal area than the space occupiedby the spring or cushioning device located within the inner wall of saidchamber and the shoulder of said cushioning device, in conjunction withthe reduced shank of the button set projecting rearwardly into the toolcylinder, whereby the requisite play to the button set and button setshoulder is provided, and my claims to these features are therefore tobe interpreted with a corresponding scope.

It will be apparent that while 1 have shown and described my inventionin one embodiment thereof as being adapted to a pneumatic riveter, thesame is equally applicable to a pneumatic chipper or in fact all otherpneumatic impact or hammering tools now on the market. g:

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent, is

1. The combination with the cylinder of a pneumatic tool, of a retainersecured to the forward end thereof and having a chamber thereinprovided, at its forward portion, with an internal wall or shoulder, aworking tool contained within said chamber and having a head of lesserdiameter than said chamber, a shoulder thereon, a spring interposedbetween said working tool shoulder and the forward inner wall of saidchamber, said spring being of less length than the distance between saidshoulder and wall, and a shank for said working tool projecting into theend of said tool cylinder, said shank being of lesser diameter than saidbutton set head and shoulder.

2. The combination of a pneumatic tool cylinder, having a reduced end, aretaining sleeve, having a chamber within it, the rear of said chamberbeing secured to said reduced end, said sleeve having an opening throughits forward portion of lesser diameter than the inner bore of saidchamber, a button set having a head of such length as to always projcctthrough said opening, said head being of lesser diameter than said bore,a shoulder on said head of greater diameter than the latter and of lessdiameter than said bore, a compressible element in said chamber of lesslength than the distance between said button set shoulder and theforward inner wall of said chamber, and a shank on said button set ofless diameter than said head and shoulder, said shank projectingrearwardly into said tool cylinder.

EDWVARD J. SHOFFNER.

Witnesses W. F. PAYNE, W. H. PAYNE.

